This invention relates to pipe fittings made of refractory material such as asbestos and also to the production thereof.
Heretofore, tubes made of plastic material such as polyvinyl chloride have been used as water supplying and draining pipes in buildings and the like, and for connecting these pipes, pipe fittings also made of plastic material are used.
Although the pipes and pipe fittings made of plastics can be easily handled and worked, and, furthermore, the costs thereof are comparatively low, the pipes and pipe fittings are easily melted at high temperatures to which they are subjected in the event of a fire in a building in which they are installed and are easily burnt to generate poisonous gases, thus constituting a serious hazard to human lives. In addition, when the pipes and pipe fittings are burnt, a great amount of heat is generated, which accelerates expansion of the fire.
Metal tubes and metal pipe fittings also have been used for water supply lines and water draining line, and these have been found advantageous because of their high mechanical strength and high heat resistance. However, metal tubes and metal pipe fittings have been accompanied by the problems of comparatively high cost and low corrosion resistance. Furthermore, the heat conductivity of metal tubes and metal pipe fittings is substantially high, and therefore when cold water flows through the interior of a pipe line made of metal tube and metal pipe fittings, dew frequently collects on the outer surface of the piping, and corrosion of the pipe line is thereby accelerated.
Pipes and pipe fittings made of refractory materials such as concrete, asbestos, portland cement, and the like are known. However, these pipes and pipe fittings are ordinarily water permeable, and it has been difficult to apply them to the construction of water supply lines and drainage lines in buildings.